gst/gstregistrybinary.*: Add crc32 checksum to the binary registry file and check...

gst/gstregistrybinary.*: Add crc32 checksum to the binary registry file and check this before accepting a registry file.

Original commit message from CVS:
* gst/gstregistrybinary.c: (_gst_crc32),
(gst_registry_binary_write),
(gst_registry_binary_initialize_magic),
(gst_registry_binary_write_cache),
(gst_registry_binary_check_magic),
(gst_registry_binary_read_cache):
* gst/gstregistrybinary.h:
Add crc32 checksum to the binary registry file and check this before
accepting a registry file.
Also free the data list when writing to the registry file fails.